U.S. patent application number 14/844758 was filed with the patent office on 2016-08-04 for image forming apparatus.
This patent application is currently assigned to FUJI XEROX CO., LTD.. The applicant listed for this patent is FUJI XEROX CO., LTD.. Invention is credited to Masaaki TAKAHASHI, Yoshiyuki TOMINAGA.
Application Number | 20160223954 14/844758 |
Document ID | / |
Family ID | 56554205 |
Filed Date | 2016-08-04 |
United States Patent
Application |
20160223954 |
Kind Code |
A1 |
TAKAHASHI; Masaaki ; et
al. |
August 4, 2016 |
IMAGE FORMING APPARATUS
Abstract
An image forming apparatus includes a first forming unit that
forms a first image with a substantially flat toner containing a
substantially flat metal pigment on a moving movable body; a second
forming unit that forms a second image with a substantially
non-flat toner on the movable body; a transfer unit that forms a
nip with the movable body while circulating and transfers the first
image and the second image on a medium transported to the nip; a
removing unit that includes a rotational body and removes the
toners adhering to the transfer unit, the rotational body having an
axis and being configured to rotate around the axis; and a
controller that, if the controller causes the first forming unit to
form the first image, stops the rotation of the rotational body
around the axis.
Inventors: |
TAKAHASHI; Masaaki;
(Kanagawa, JP) ; TOMINAGA; Yoshiyuki; (Kanagawa,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJI XEROX CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
FUJI XEROX CO., LTD.
Tokyo
JP
|
Family ID: |
56554205 |
Appl. No.: |
14/844758 |
Filed: |
September 3, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03G 2215/0129 20130101;
G03G 15/1605 20130101; G03G 15/168 20130101; G03G 21/0035
20130101 |
International
Class: |
G03G 15/16 20060101
G03G015/16 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 3, 2015 |
JP |
2015-019432 |
Claims
1. An image forming apparatus, comprising: a first forming unit
configured to form a first image with a substantially flat toner
containing a substantially flat metal pigment on a moving movable
body; a second forming unit configured to form a second image with
a substantially non-flat toner on the movable body; a transfer unit
configured to form a nip with the movable body while circulating
and configured to transfer the first image and the second image on
a medium transported to the nip; a removing unit comprising a
rotational body and configured to remove the toners adhering to the
transfer unit, the rotational body configured to rotate around an
axis of the rotational body; and a controller configured to stop
the rotation of the rotational body around the axis at a time when
the transfer unit transfers the first image to the medium.
2. The image forming apparatus according to claim 1, wherein the
substantially non-flat toner has a substantially spherical
shape.
3. An image forming apparatus, comprising: a first forming unit
configured to form a first image with a substantially flat toner
containing a substantially flat metal pigment on a moving movable
body; a second forming unit configured to form a second image with
a substantially non-flat toner on the movable body; a transfer unit
configured to form a nip with the movable body while circulating
and configured to transfer the first image and the second image on
a medium transported to the nip; a removing unit comprising a
rotational body and configured to remove the toners adhering to the
transfer unit, the rotational body configured to rotate around an
axis of the rotational body; and a controller configured to stop
the rotation of the rotational body around the axis at a time when
the controller controls the first forming unit to form the first
image, the first image corresponding to a first image satisfying a
predetermined condition.
4. The image forming apparatus according to claim 3, wherein the
substantially non-flat toner has a substantially spherical
shape.
5. The image forming apparatus according to claim 3, wherein, at a
time when the controller controls the first forming unit to form
the first image that does not satisfy the predetermined condition,
the controller is configured to control the rotational body to
rotate around the axis.
6. The image forming apparatus according to claim 3, wherein each
of the first forming unit and the second forming unit is configured
to form a non-transfer image that is not transferred on the medium
transported to the nip, and wherein, at a time when the controller
controls the first forming unit to form the first image that
satisfies the predetermined condition, the controller is configured
to control the first forming unit or the second forming unit to not
form the non-transfer image.
7. An image forming apparatus, comprising: a first forming unit
configured to form a first image with a substantially flat toner
containing a substantially flat metal pigment on a moving movable
body; a second forming unit configured to form a second image with
a substantially non-flat toner on the movable body; a transfer unit
configured to form a nip with the movable body while circulating
and configured to transfer the first image and the second image on
a medium transported to the nip; a removing unit comprising a
rotational body and configured to remove the toners adhering to the
transfer unit, the rotational body configured to rotate around an
axis of the rotational body; and a controller configured to stop
the rotation of the rotational body around the axis at a time when
the controller controls the first forming unit to form the first
image that satisfies a predetermined condition, wherein the
rotational body is conductive and is configured to contact the
transfer unit, wherein the image forming apparatus further
comprises an applying unit configured to apply a voltage to the
rotational body, the voltage causing the toners to be transferred
from the transfer unit to the rotational body, and wherein, at a
time when the controller controls the first forming unit to form
the first image that satisfies the predetermined condition, the
controller is configured to control the applying unit to apply the
voltage.
8. The image forming apparatus according to claim 7, wherein each
of the first forming unit and the second forming unit is configured
to form a non-transfer image that is not transferred on the medium
transported to the nip, and wherein, at a time when the controller
controls the first forming unit to form the first image that does
not satisfying the predetermined condition, the controller is
configured to control the first forming unit to form the
non-transfer image, configured to control the rotational body to
rotate around the axis, and configured to control the applying unit
to apply the voltage.
9. The image forming apparatus according to claim 7, wherein the
removing unit comprises a removing portion configured to contact
the rotational body rotating around the axis and configured to
remove the toners from the rotational body, and wherein, at a time
when the controller controls the first forming unit to form the
first image that satisfies the predetermined condition, the
controller is configured to control the transfer unit to end the
transfer of the first image, which is formed by the first forming
unit in response to a command, on the medium, and then the
controller is configured to control the rotational body to rotate
around the axis.
10. The image forming apparatus according to claim 3, wherein the
predetermined condition corresponds to a condition where a transfer
width of the first image with respect to a width of the medium in a
direction intersecting with a transport direction of the medium is
larger than or equal to a predetermined width, and an area coverage
of the first image is greater than or equal to a predetermined area
coverage.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
USC 119 from Japanese Patent Application No. 2015-019432 filed Feb.
3, 2015.
BACKGROUND
[0002] The present invention relates to an image forming
apparatus.
SUMMARY
[0003] According to an aspect of the invention, there is provided
an image forming apparatus including a first forming unit that
forms a first image with a substantially flat toner containing a
substantially flat metal pigment on a moving movable body; a second
forming unit that forms a second image with a substantially
non-flat toner on the movable body; a transfer unit that forms a
nip with the movable body while circulating and transfers the first
image and the second image on a medium transported to the nip; a
removing unit that includes a rotational body and removes the
toners adhering to the transfer unit, the rotational body having an
axis and being configured to rotate around the axis; and a
controller that, if the controller causes the first forming unit to
form the first image, stops the rotation of the rotational body
around the axis.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Exemplary embodiments of the present invention will be
described in detail based on the following figures, wherein:
[0005] FIG. 1 is schematic view (front view) of an image forming
apparatus according to a first exemplary embodiment;
[0006] FIG. 2 is a schematic view (front view) of a toner image
forming unit configuring the image forming apparatus according to
the first exemplary embodiment;
[0007] FIG. 3 is a schematic view of a peripheral area of a second
transfer unit of a transfer device configuring the image forming
apparatus according to the first exemplary embodiment;
[0008] FIG. 4 is a schematic view (cross-sectional view) of a toner
particle of a flat toner that is used by the image forming
apparatus according to the first exemplary embodiment;
[0009] FIG. 5 is a schematic view (cross-sectional view) of a toner
particle of a non-flat toner that is used by the image forming
apparatus according to the first exemplary embodiment;
[0010] FIG. 6 is a schematic view showing a state in which a toner
image and a non-transfer image are held by a transfer belt in the
image forming apparatus according to the first exemplary
embodiment;
[0011] FIGS. 7A and 7B are each an illustration showing a flat
toner held on a transfer belt of the image forming apparatus
according to the first exemplary embodiment, FIG. 7A being a
schematic view showing a flat toner configuring a toner image
within a dotted-line area VIIA in FIG. 1, FIG. 7B being a schematic
view showing a flat toner configuring a toner image within a
dotted-line area VIIB in FIG. 1;
[0012] FIG. 8 is a flowchart when a controller configuring the
image forming apparatus according to the first exemplary embodiment
controls the second transfer unit during a transfer operation;
[0013] FIG. 9 is a schematic view showing a predetermined condition
of the controller in the flowchart in FIG. 8, in the image forming
apparatus according to the first exemplary embodiment;
[0014] FIG. 10 is a graph showing a test result that serves as the
basis of the predetermined condition in FIG. 9;
[0015] FIG. 11A is a schematic view showing an image on a medium
formed by an image forming apparatus according to a comparative
exemplary embodiment, FIG. 11B is a partial cross-sectional view
taken along line XIB-XIB in FIG. 11A, and FIG. 11C is a partial
cross-sectional view taken along line XIC-XIC in FIG. 11A;
[0016] FIG. 12 is a flowchart when a controller configuring an
image forming apparatus according to a second exemplary embodiment
controls a second transfer unit during a transfer operation;
[0017] FIG. 13 is a schematic view of a peripheral area of a second
transfer unit of a transfer device configuring an image forming
apparatus according to a third exemplary embodiment;
[0018] FIG. 14 is a flowchart when a controller configuring the
image forming apparatus according to the third exemplary embodiment
controls the second transfer unit during a transfer operation;
[0019] FIG. 15 is a schematic view of a peripheral area of a second
transfer unit of a transfer device configuring an image forming
apparatus according to a fourth exemplary embodiment;
[0020] FIG. 16 is a flowchart when a controller configuring the
image forming apparatus according to the fourth exemplary
embodiment controls the second transfer unit during a transfer
operation; and
[0021] FIG. 17 is a flowchart when a controller configuring an
image forming apparatus according to other exemplary embodiment
controls a second transfer unit during a transfer operation.
DETAILED DESCRIPTION
Overview
[0022] Exemplary embodiments for implementing the invention
(hereinafter, referred to as exemplary embodiments) are described
below. In the description of the exemplary embodiments, first to
fourth exemplary embodiments are provided. In the following
description, directions indicated by arrow X and arrow -X in the
drawings represent an apparatus width direction, and directions
indicated by arrow Y and arrow -Y in the drawings represent an
apparatus height direction. Also, directions (arrow Z and arrow -Z
directions) orthogonal to the apparatus width direction and the
apparatus height direction represent an apparatus depth
direction.
First Exemplary Embodiment
[0023] This exemplary embodiment is described below with reference
to the drawings. First, a configuration of an image forming
apparatus 10 (see FIG. 1) according to this exemplary embodiment is
described. Then, an image forming operation of the image forming
apparatus 10 of this exemplary embodiment is described. Then,
effects of this exemplary embodiment are described.
Configuration of Image Forming Apparatus
[0024] First, a general configuration of the image forming
apparatus 10 is described, and then, major portions (a transfer
device 30, a second transfer unit 36 (see FIG. 3) configuring the
transfer device 30, and a toner (see FIGS. 4 and 5) used by the
image forming apparatus 10) are described.
General Configuration of Image Forming Apparatus
[0025] As shown in FIG. 1, the image forming apparatus 10 is an
electrophotographic apparatus including a toner image forming unit
20, a transfer device 30, a transport device 40, a fixing device
50, a controller 60, and a power supply PS. In the image forming
apparatus 10 of this exemplary embodiment, an example of a medium P
on which an image may be formed is a cut sheet.
Toner Image Forming Unit
[0026] The toner image forming unit 20 has a function of forming a
toner image G1 (see FIGS. 1 and 6) and a non-transfer image G2 (see
FIG. 6) held on a transfer belt TB (described later), which
configures the transfer device 30, by executing respective
processes of electric charge, exposure, and development. In this
exemplary embodiment, the toner image G1 represents a toner image
to be second transferred on a medium P. In contrast, the
non-transfer image G2 is not a toner image to be second
transferred, but the non-transfer image G2 is a toner image to be
formed for maintaining an electrically charged state etc. of
respective toners MT and NT (for example, for restricting excessive
electric charge of the toners MT and NT) housed in developing
devices 28G, 28Y, 28M, 28C, and 28K (described later). For example,
the image forming apparatus 10 of this exemplary embodiment is
configured such that the non-transfer image G2 is first transferred
on a portion of the transfer belt TB which does not contact the
medium P at a nip N2 (described later) of the transfer belt TB, and
the non-transfer image G2 is removed by a blade 38 (described
later) (see FIG. 6). In the following description, the toners MT
and NT are described as a toner T unless otherwise the toner MT and
the toner NT are particularly required to be distinguished from one
another.
[0027] The toner image forming unit 20 includes single-color units
21G, 21Y, 21M, 21C, and 21K that form toner images G1 of different
colors (G (gold), Y (yellow), M (magenta), C (cyan), K (black)).
The single-color units 21G, 21Y, 21M, 21C, and 21K have similar
configurations except the colors of the respectively formed toner
images G1. Hereinafter, in the specification and drawings, the
alphabets (G, Y, M, C, K) of the single-color units 21G, 21Y, 21M,
21C, and 21K are omitted unless otherwise the single-color units
21G, 21Y, 21M, 21C, and 21K and their components are required to be
distinguished from one another. The single-color unit 21G forms a
toner image G1 and a non-transfer image G2 with a flat or
substantially flat toner MT (hereinafter, referred to as toner MT,
see FIG. 4), which is described later, on the transfer belt TB
(described later). The single-color units 21 other than the
single-color unit 21G each form a toner image G1 and a non-transfer
image G2 with a non-flat or substantially non-flat toner NT
(hereinafter, referred to as toner NT, see FIG. 5), which is
described later, on the transfer belt TB. The toner MT and the
toner NT of this exemplary embodiment each have, for example,
negative polarity (average of charge amount distribution is
negative). The single-color unit 21G is an example of a first
forming unit, and the single-color units 21 other than the
single-color unit 21G are each an example of a second forming unit.
Also, the toner image G1 formed by the single-color unit 21G is an
example of a first image, and the toner image G1 formed by each of
the single-color units 21 other than the single-color unit 21G is
an example of a second image.
[0028] As shown in FIGS. 1 and 2, each single-color unit 21
includes a photoconductor 22, a charging device 24, an exposure
device 26, a developing device 28, and a first transfer roller 29.
The photoconductor 22 is cylindrical, and its axis (representing
the axis of the photoconductor 22) is arranged along the apparatus
depth direction. The first transfer roller 29 forms a nip N1 with
the photoconductor 22 with the transfer belt TB interposed
therebetween. The charging device 24 electrically charges the
photoconductor 22, the exposure device 26 exposes the
photoconductor 22 rotating around its axis, to light, and the
developing device 28 develops the toner image G1 and the
non-transfer image G2. Thus, each single-color unit 21 forms the
toner image G1 and the non-transfer image G2 on the photoconductor
22. Also, a first transfer voltage (voltage with positive polarity)
is applied from the power supply PS to each first transfer roller
29, and hence the first transfer roller 29 first transfers the
toner image G1 and the non-transfer image G2 formed on the
photoconductor 22, on the moving (circulating) transfer belt TB at
the nip N1. The exposure device 26 forms, for example, a latent
image on the photoconductor 22 with a minimum exposure dot
corresponding to 1200 dpi.times.1200 dpi (about 21
.mu.m.times.about 21 .mu.m). In FIG. 1, the reference signs for the
components of the single-color units 21 other than those of the
single-color unit 21K are omitted.
Transfer Device
[0029] The transfer device 30 has a function of second transferring
the toner images G1 and the non-transfer image G2 of the respective
colors formed by the respective single-color units 21 and first
transferred at the nips N1, on a medium P transported to a nip N2
(described later). The configuration of the transfer device 30 is
described later.
Transport Device
[0030] The transport device 40 has a function of transporting a
medium P. If image formation is executed on plural media P during
an image forming operation, the transport device 40 transports the
plural media P at predetermined intervals interposed among the
continuously transported media P.
Fixing Device
[0031] The fixing device 50 has a function of applying heat and
pressure at a nip N3 to the toners T configuring the toner images
G1 of the respective colors second transferred on the medium P by
the transfer device 30, and hence fixing the toners T to the medium
P. The fixing device 50 includes a heating portion 50A and a
pressing portion 50B.
Controller
[0032] The controller 60 has a function of controlling respective
units other than the controller 60 configuring the image forming
apparatus 10.
[0033] The controller 60 receives image data from an external
device (not illustrated). The controller 60 which has received the
image data controls the respective units other than the controller
60 configuring the image forming apparatus 10 by following, for
example, a flowchart in FIG. 8. The controller 60 that executes
control shown in the flowchart in FIG. 8 is described in detail in
the description for an image forming operation of the image forming
apparatus 10. In this section, a predetermined condition in step
S210 in the flowchart in FIG. 8 is described. When the controller
60 receives image data from an external device, the controller 60
receives other data (for example, data indicating the number of
media P, on which images are formed), from the external device.
Also, the controller 60 causes the image forming apparatus 10 to
execute the image forming operation in accordance with job data
(data containing image data and data indicating the number of media
P, or command).
[0034] If the controller 60 determines that a toner image G1 with a
gold-color toner MT satisfies a predetermined condition (if the
controller 60 determines YES), the controller 60 causes the image
forming apparatus 10 to execute an image forming operation in a
special mode. In contrast, if the controller 60 determines that the
condition is not satisfied (if the controller 60 determines NO) in
determining step S210, the controller 60 causes the image forming
apparatus 10 to execute an image forming operation in a normal
mode. The specific contents of the special mode and the normal mode
are described later.
Predetermined Condition
[0035] For example, as shown in FIG. 9, the predetermined condition
uses a ratio of a formation width of the toner MT (the maximum
width in which the toner MT is formed) with respect to the width of
a medium P, and an area coverage [%] of the toner MT as parameters.
In this exemplary embodiment, it is assumed that the predetermined
condition is satisfied if the ratio of the formation width of the
toner MT with respect to the width of the medium P on which image
formation is actually executed in accordance with job data is 2/3
or larger (1 or smaller) and the area coverage of the toner MT is
95% or higher (100% or lower) (if the toner image G1 is included in
a region A1 in FIG. 9). The area coverage of the toner MT
represents the percentage of the pixels in the axial direction of
the photoconductor 22G that is exposed to light by the exposure
device 26G (the pixels in the axial direction of the photoconductor
22G having the toner image G1 with the toner MT that is developed
by the developing device 28) with respect to the pixels included in
the formation width of the toner MT when the minimum exposure dot
formed by the exposure device 26G on the photoconductor 22G is one
pixel. For example, if the area coverage of the toner MT is 100%,
the toner MT is developed and transferred in all pixels included in
the formation width of the toner MT. Also, if the area coverage of
the toner MT is 50%, the toner MT is developed and transferred in
half of pixels included in the formation width of the toner MT. In
this exemplary embodiment, the basis of the determination that the
predetermined condition is satisfied if the toner image G1 is
included in the region A1 in FIG. 9 is described later.
[0036] The above description is for the general configuration of
the image forming apparatus 10 of this exemplary embodiment.
Configuration of Major Portions of Image Forming Apparatus
[0037] Next, the transfer device 30, the second transfer unit 36
configuring the transfer device 30, and the toners MT and NT used
in the image forming apparatus 10 being major portions of the image
forming apparatus 10 are described with reference to the
drawings.
Transfer Device
[0038] As shown in FIG. 1, the transfer device 30 includes the
transfer belt TB, a driving roller 32, a tension roller 34, the
second transfer unit 36, and a blade 38.
Transfer Belt, Driving Roller, and Tension Roller
[0039] The transfer belt TB is endless. The driving roller 32 is
driven by a driving source (not illustrated), and moves the
transfer belt TB in the arrow R direction while rotating around its
axis. The tension roller 34 presses the transfer belt TB from the
inner periphery side, and gives a tension to the transfer belt TB.
With the above-described configuration, the toner images G1 and the
non-transfer images G2 of the respective colors formed by the
respective single-color units 21 are first transferred on the
transfer belt TB while the transfer belt TB moves in the arrow R
direction. The transfer belt TB causes the toner images G1 and the
non-transfer images G2 of the respective colors to reach the nip N2
while being held on the outer periphery. The transfer belt TB is an
example of a movable body.
Second Transfer Unit
[0040] The second transfer unit 36 has a function of second
transferring the toner images G1 of the respective colors held on
the transfer belt TB, on a medium P transported by the transport
device 40. As shown in FIGS. 1 and 3, the second transfer unit 36
includes a second transfer portion 70, a backup roller 80
(hereinafter, referred to as BUR 80), and a removing unit 90.
Second Transfer Portion and BUR
[0041] The second transfer portion 70 includes a conductive roller
72, a tension roller 74, and a conductive belt CB. The conductive
belt CB is an example of a transfer unit.
[0042] The conductive belt CB has a function of forming the nip N2
with the transfer belt TB while the conductive belt CB circulates,
and transferring a toner image G1 on a medium P transported to the
nip N2 by the transport device 40. The conductive roller 72
includes a shaft 72A, and a cylindrical conductive layer 72B. The
conductive roller 72 is driven by a driving source (not
illustrated) and rotates around its axis. The conductive belt CB is
endless, and is wound around the cylindrical conductive layer 72B.
The tension roller 74 presses the conductive belt CB from the inner
periphery side, and gives a tension to the conductive belt CB. With
the above-described configuration, in the second transfer portion
70, the conductive belt CB circulates when the conductive roller 72
rotates around its axis. The shaft 72A of the conductive roller 72
is grounded.
[0043] As shown in FIGS. 1 and 3, the BUR 80 is arranged at the
opposite side (upper side) of the second transfer portion 70 with
the transfer belt TB interposed therebetween. Also, the BUR 80
causes the conductive belt CB and the transfer belt TB to form the
nip N2 at a position offset with respect to the conductive roller
72.
[0044] The BUR 80 includes a shaft 80A, and a cylindrical
conductive layer 80B. A voltage is applied from the power supply PS
(see FIG. 1) to the shaft 80A of the BUR 80. To be specific, a
second transfer voltage (voltage with negative polarity) is applied
from the power supply PS to the BUR 80 when a medium P passes
through the nip N2. Consequently, the conductive belt CB forms an
electric field for second transferring the toner image G1 on the
medium P at the nip N2 together with the transfer belt TB. Also, a
voltage with positive polarity is applied from the power supply PS
to the BUR 80 before and after the medium P passes through the nip
N2. Consequently, the conductive belt CB forms an electric field
for causing the transfer belt TB to hold the non-transfer image G2
at the nip N2 together with the transfer belt TB.
[0045] With the above-described configuration, the conductive belt
CB forms the nip N2 together with the transfer belt TB while
circulating, and transfers the toner image G1 on the transported
medium P in a period in which the medium P passes through the nip
N2. Also, the conductive belt CB forms the nip N2 together with the
transfer belt TB while circulating, and allows the transfer belt TB
to pass through the nip N2 while the transfer belt TB holds the
non-transfer image G2 before and after the medium P passes through
the nip N2.
Removing Unit
[0046] The removing unit 90 has a function of removing a toner T
adhering to the conductive belt CB. As shown in FIG. 3, the
removing unit 90 includes a first removing portion 92, a second
removing portion 94, and a housing 96. The first removing portion
92 and the second removing portion 94 are arranged in the housing
96.
[0047] The first removing portion 92 has a function of removing a
toner T electrically charged with negative polarity. The first
removing portion 92 includes a conductive brush 92A and a metal
shaft 92B. The conductive brush 92A and the metal shaft 92B are
each an example of a rotational body. Also, the metal shaft 92B is
an example of a removing portion. The conductive brush 92A contacts
(bites into) a portion of the conductive belt CB wound around the
conductive roller 72. Also, the conductive brush 92A contacts the
metal shaft 92B at a portion different from a portion of the
conductive brush 92A biting into the conductive belt CB. The
conductive brush 92A and the metal shaft 92B are arranged so that
the axial directions of the conductive brush 92A and the metal
shaft 92B are aligned with the axial direction of the conductive
roller 72.
[0048] The second removing portion 94 has a function of removing a
toner T electrically charged with positive polarity. The second
removing portion 94 is arranged at a portion located downstream of
the first removing portion 92 and located upstream of the nip N2 in
a circulation direction of the conductive belt CB. The second
removing portion 94 includes a conductive brush 94A and a metal
shaft 94B. The conductive brush 94A and the metal shaft 94B are
each another example of a rotational body. Also, the metal shaft
94B is an example of a removing portion. The conductive brush 94A
contacts a portion of the conductive belt CB, the portion which is
wound around the conductive roller 72 and is different from the
portion into which the conductive brush 92A bites. Also, the
conductive brush 94A contacts the metal shaft 94B at a portion of
the conductive brush 94A different from a portion biting into the
conductive belt CB. The conductive brush 94A and the metal shaft
94B are arranged so that the axial directions of the conductive
brush 92A and the metal shaft 92B are aligned with the axial
direction of the conductive roller 72.
[0049] When the metal shaft 94B is driven by a driving source (not
illustrated), the metal shaft 94B rotates counterclockwise in a
view from the near side in the apparatus depth direction. Also, a
torque is transmitted to the conductive brushes 92A and 94A, and
the metal shaft 92B through a gear (not illustrated) meshing with a
gear (not illustrated) provided at the metal shaft 94B.
Consequently, the metal shaft 92B rotates counterclockwise, and the
conductive brushes 92A and 94A rotate clockwise. As described
above, in this exemplary embodiment, the conductive brushes 92A and
94A, and the metal shaft 92B are rotated when the metal shaft 94B
rotates, and are stopped when the metal shaft 94B stops.
[0050] When a voltage with positive polarity is applied from the
power supply PS to the metal shaft 92B, the conductive brush 92A is
electrically charged with positive polarity and rotates around its
axis. The conductive brush 92A transfers a toner T with negative
polarity from the conductive belt CB, and then the metal shaft 92B
removes the toner T from the conductive brush 92A. That is, a
voltage that causes the toner T with negative polarity to be
transferred from the conductive belt CB is applied to the
conductive brush 92A. When a voltage with negative polarity is
applied from the power supply PS to the metal shaft 94B, the
conductive brush 94A is electrically charged with negative polarity
and rotates around its axis. The conductive brush 94A transfers a
toner T with positive polarity from the conductive belt CB, and
then the metal shaft 94B removes the toner T from the conductive
brush 94A. That is, a voltage that causes the toner T with positive
polarity to be transferred from the conductive belt CB is applied
to the conductive brush 94A. The toners T removed by the metal
shafts 92B and 94B are scraped by blades (not illustrated) from the
metal shafts 92B and 94B, and are housed in the housing 96.
Blade
[0051] The blade 38 has a function of removing a toner T not second
transferred on a medium P transported to the nip N2 but remaining
on the transfer belt TB and a toner T configuring the non-transfer
image G2 held on the transfer belt TB from the transfer belt TB. As
shown in FIG. 1, the blade 38 contacts the transfer belt TB at a
position located downstream of the nip N2 and upstream of the toner
image forming unit 20 (the single-color unit 21G) in the moving
direction of the transfer belt TB (the arrow R direction).
Toner
Flat Toner (Toner MT)
[0052] As shown in FIG. 4, for example, a toner particle MTP
configuring the toner MT contains a metal pigment MP and a binder
BD. The binder BD covers the metal pigment MP. The metal pigment MP
is flat or substantially flat. To be specific, the metal pigment MP
has a long-axis length L1, for example, in a range from 5 .mu.m to
12 .mu.m, and a thickness T1, for example, in a range from 0.01
.mu.m to 0.5 .mu.m. In this case, the long-axis length L1
represents a length of a portion with the largest length of the
metal pigment MP when the metal pigment MP is viewed in a direction
orthogonal to the thickness direction of the metal pigment MP. The
toner particle MTP of this exemplary embodiment has a long-axis
length L2, for example, in a range from 7 .mu.m to 20 .mu.m, and a
thickness T2, for example, in a range from 1 .mu.m to 3 .mu.m. In
this case, the long-axis length L2 represents a length of a portion
with the largest length of the toner particle MTP when the toner
particle MTP is viewed in a direction orthogonal to the thickness
direction of the toner particle MTP. As described above, the toner
particle MTP of this exemplary embodiment is a toner particle
having relationships that (long-axis length L1)/(thickness T1) of
the contained metal pigment MP is, for example, in a range from 10
to 1200, and (long-axis length L2)/(thickness T2) of the toner
particle MTP is, for example, in a range from 2.3 to 20 (the toner
MT of this exemplary embodiment being a group of the toner
particles MTP having the above-described relationships). As
described above, the toner MT of this exemplary embodiment is gold
color. The gold color is made by using, for example, aluminum for
the metal pigment MP configuring the toner particle MTP, and
dispersing, for example, a pigment of yellow (Y) in the binder
BD.
Non-Flat Toner (Toner NT)
[0053] As shown in FIG. 5, a toner particle NTP configuring the
toner NT contains, for example, a resin pigment RP and a binder BD.
Also, the toner particle NTP is not flat. To be specific, the toner
particle NTP of this exemplary embodiment represents a toner
particle having relationships that (long-axis length)/(thickness)
of the contained resin pigment RP is, for example, smaller than 10,
and (long-axis length)/(thickness) of the toner particle NTP is,
for example, smaller than 2.3. Also, the circularity of the toner
particle NTP of this exemplary embodiment when the toner particle
NTP is projected on a flat plane is, for example, 0.90 or larger.
Thus, the toner particle NTP (the toner NT) of this exemplary
embodiment is a non-flat toner particle (a toner).
[0054] The above description is for the configurations of the major
portions of the image forming apparatus 10 and the toners MT and NT
used by the image forming apparatus 10 according to this exemplary
embodiment.
Supplemental Explanation
[0055] Supplemental explanation is given below for the
configuration of the image forming apparatus 10 of this exemplary
embodiment.
Supplemental Explanation 1
[0056] As shown in each of FIGS. 7A and 7B, the toner MT is held at
the transfer belt TB in a state (a standing state) in which the
long axis (the axis in the longitudinal direction) of the toner MT
is along a direction substantially orthogonal to the outer
periphery of the transfer belt TB while the toner MT moves with the
transfer belt TB at a portion other than the nip N1 and N2. This
may be expectedly because the toner MT is polarized in the
direction along the long-axis direction of the toner MT. Also, the
toner MT adhering to the transfer belt TB in the standing state
changes in posture expectedly because the toner MT is pinched by
the photoconductor 22 and the transfer belt TB at the nip N1 and is
pinched by the conductive belt CB of the second transfer portion 70
and the transfer belt TB at the nip N2.
Supplemental Explanation 2
[0057] As described above, in the image forming apparatus 10
according to this exemplary embodiment, the non-transfer image G2
is first transferred on a portion (inter-image portion) of the
transfer belt TB, the portion which does not contact a medium P at
the nip N2. A portion surrounded by a broken line PA in FIG. 6
indicates a portion of the transfer belt TB which contacts a medium
P at the nip N2. Also, in this exemplary embodiment, a portion
arranged between portions surrounded by two neighbor broken lines
PA on the transfer belt TB is a portion of the transfer belt TB on
which the non-transfer image G2 is first transferred.
Supplemental Explanation 3
[0058] As described above, in the image forming apparatus 10 of
this exemplary embodiment, when the toner image G1 is formed by
using the single-color unit 21G, an image using the flat metal
pigment MP as a coloring matter is formed. When an image is formed
by using the toner MT configured of the toner particle MTP
containing the flat metal pigment MP, the image reflects light and
hence has glossiness.
Image Forming Operation of Image Forming Apparatus
[0059] An image forming operation of the image forming apparatus 10
of this exemplary embodiment is described with reference to the
drawings. In the following description, a basic operation of the
image forming apparatus 10 is described first, and an operation
executed every different image data received from an external
device (not illustrated) is described next. In this case, the basic
operation of the image forming apparatus 10 represents an operation
that is executed commonly even if image data is different.
Basic Operation
[0060] The controller 60 which has received image data (for
example, data for forming an image on plural media P) from an
external device (not illustrated) activates the toner image forming
unit 20, the transfer device 30, and the fixing device 50.
[0061] The controller 60 causes the charging device 24 to
electrically charge the photoconductor 22, causes the exposure
device 26 to expose the photoconductor 22 to light, and causes the
developing device 28 to develop a toner image G1 and a non-transfer
image G2. Then, when the controller 60 causes the power supply PS
to apply a first transfer voltage to each first transfer roller 29,
the first transfer roller 29 first transfers the toner image G1 and
the non-transfer image G2 on the moving transfer belt TB.
Consequently, as shown in FIG. 6, the toner image forming unit 20
forms respective toner images G1 and respective non-transfer images
G2 on the transfer belt TB.
[0062] Also, the controller 60 drives a driving source (not
illustrated) of the conductive roller 72, the BUR 80, and the
removing unit 90 of the second transfer unit 36, causes the
conductive belt CB to circulate, causes the conductive brushes 92A
and 94A to be rotated around their axes, and causes the heating
portion 50A to be heated.
[0063] Then, the controller 60 causes the transport device 40 to
transport a medium P to N2 in synchronization with a timing at
which the respective toner images G1 first transferred and held on
the transfer belt TB reach the nip N2 together with the transfer
belt TB. Then, the controller 60 causes the power supply PS to
apply a second transfer voltage to the shaft 80A of the BUR 80, and
causes the toner image G1 held on the transfer belt TB to be second
transferred on the medium P passing through the nip N2. Then, after
the medium P passes through the nip N2, the controller 60 causes
the power supply PS to apply a voltage with positive polarity to
the shaft 80A, and causes the conductive belt CB to form an
electric field for causing the transfer belt TB to hold the
non-transfer image G2 on the transfer belt TB passing through the
nip N2. Consequently, the non-transfer image G2 on the transfer
belt TB is moved together with the transfer belt TB and is removed
from the transfer belt TB by the blade 38.
[0064] Then, the controller 60 causes the transport device 40 to
transport the medium P to the nip N3. The controller 60 causes the
heating portion 50A to heat the toner image G1 second transferred
on the medium P and causes the pressing portion 50B to press the
toner image G1. Consequently, the toner image G1 on the medium P is
fixed to the medium P, the medium P is output to the outside of the
image forming apparatus 10 by the transport device 40, and the
image forming operation of the image forming apparatus 10 is
ended.
[0065] The toner T adhering to the conductive belt CB (for example,
so-called fog toner) circulates together with the conductive belt
CB, and is removed from the conductive belt CB by the conductive
brushes 92A and 94A configuring the removing unit 90.
[0066] The above description is for the basic operation of the
image forming apparatus 10.
Operation Per Image Data
[0067] Next, an operation per different image data received from an
external device (not illustrated) is described (for example, the
image data being data for forming an image on plural media P).
Operation if Image Data Forming Toner Image G1 with Toner MT is not
Included
[0068] In this case, as shown in FIG. 8, the controller 60
determines NO in determining step S200, and causes the image
forming apparatus 10 to execute an image forming operation in the
normal mode. To be specific, the controller 60 causes the
single-color unit 21 that forms a toner image G1 with a color
included in the image data to form a toner image G1 and a
non-transfer image G2 (step S250). Also, the controller 60 causes
the first removing portion 92 and the second removing portion 94 of
the removing unit 90 configuring the second transfer unit 36 to be
driven (causes the conductive brushes 92A and 94A to rotate around
their axes), and causes the power supply PS to apply a voltage to
the metal shafts 92B and 94B (step S260). Image formation on plural
media P, which are requested for image formation, is executed and
the image forming operation is ended.
Operation if Image Data Forming Toner Image G1 with Toner MT is
Included
[0069] In this case, as shown in FIG. 8, the controller 60
determines YES under the condition in determining step S200, and
makes determination in determining step S210.
[0070] If the controller 60 determines NO in determining step S210,
the controller 60 causes the image forming apparatus 10 to execute
an image forming operation in the normal mode. Image formation on
plural media P, which are requested for image formation, is
executed and the image forming operation is ended.
[0071] In contrast, if the controller 60 determines YES in
determining step S210, the controller 60 causes the image forming
apparatus 10 to execute an image forming operation in the special
mode. To be specific, the controller 60 causes the single-color
unit 21 that forms a toner image G1 with a color included in the
image data to form a toner image G1 and a non-transfer image G2
(step S220). Also, the controller 60 does not cause the first
removing portion 92 or the second removing portion 94 of the
removing unit 90 configuring the second transfer unit 36 to be
driven (does not cause the conductive brush 92A or 94A to rotate
around its axis), and causes the power supply PS to apply a voltage
to the metal shafts 92B and 94B (step S230). After the transfer
operation for all toner images G1 and non-transfer images G2 on the
plural media P requested for the transfer (second transfer) is
ended, the controller 60 causes the second transfer unit 36 to
execute a maintenance operation. To be specific, the controller 60
causes the power supply PS to apply a voltage to the metal shafts
92B and 94B, and causes the first removing portion 92 and the
second removing portion 94 to be driven (causes the conductive
brushes 92A and 94A and the metal shafts 92B and 94B to rotate
plural times around their axes). Also, the controller 60 causes the
conductive roller 72 of the second transfer portion 70 to rotate
around its axis and causes the driving roller 32 of the transfer
device 30 to rotate around its axis. Thus, the image forming
operation is ended.
Effect
[0072] Next, effects of this exemplary embodiment are
described.
[0073] First, effects (first to fourth effects) of this exemplary
embodiment are described with reference to the drawings. In the
following description, when effects of this exemplary embodiment
are compared with effects of comparative exemplary embodiments, and
when the components used in this exemplary embodiment are used in
the comparative exemplary embodiments, the reference signs of the
components are used without being changed.
First Effect
[0074] A first effect of this exemplary embodiment is an effect of
not driving the first removing portion 92 or the second removing
portion 94 in step S230 in the special mode if the controller 60
determines YES in determining step S200 and determining step S210
in FIG. 8.
[0075] For the first effect, the image forming apparatus 10 (the
transfer device 30) of this exemplary embodiment is described in
comparison with an image forming apparatus (a transfer device) of a
comparative exemplary embodiment described below. The image forming
apparatus (a controller) of the comparative exemplary embodiment is
configured to drive the first removing portion 92 and the second
removing portion 94 to be driven in step S230 in FIG. 8. The image
forming apparatus of the comparative exemplary embodiment has a
similar configuration to that of the image forming apparatus 10
(the transfer device 30) of this exemplary embodiment except the
above-described point.
[0076] In the case of the image forming apparatus of the
comparative exemplary embodiment, if the controller 60 determines
YES in determining step S200 and in determining step S210, the
toner image G1 on the transfer belt TB is second transferred on a
medium P at the nip N2 while the first removing portion 92 and the
second removing portion 94 are driven (rotated). If the metal shaft
94B is rotated around its axis by a driving source (not
illustrated), the conductive roller 72 configuring the second
transfer portion 70 vibrates in the apparatus depth direction and
the apparatus height direction by the rotation of gears (not
illustrated) of the conductive brushes 92A and 94A and the metal
shafts 92B and 94B. The conductive belt CB also vibrates in the
apparatus depth direction and the apparatus height direction by the
vibration of the conductive roller 72. Consequently, in the case of
the comparative exemplary embodiment, the toner MT (the toner MT
configuring the toner image G1) adhering to the transfer belt TB in
the standing state falls to the transfer belt TB alternately at the
near side or the far side in the apparatus depth direction (one
side or the other side in the width direction of the medium P), and
is second transferred on the medium P in synchronization with the
passing timing. Then, as shown in FIGS. 11A to 11C, if the toner MT
configuring the second transferred toner image G1 is fixed to the
medium P, an image is formed with a periodical variation in posture
of the flat metal pigment MP inclined to the medium P alternately
at the one side or the other side in the width direction of the
medium P for a vibration period of the conductive roller 72. Then,
if the toner image G1 with MT satisfies the predetermined condition
(if included in the region A1 in FIG. 9), arrangement unevenness of
the flat metal pigment MP is more likely visually recognized than
the case not satisfying the predetermined condition.
[0077] The predetermined condition is supplementary described. It
may be expectedly considered that the toner MT more likely slips
between the transfer belt TB and the medium P at the nip N2 as the
formation width of the toner image G1 with the toner MT is larger
and as the area coverage of the toner MT is higher. As described
above, since the conductive belt CB vibrates in the apparatus depth
direction and the apparatus height direction, it may be expectedly
considered that the toner MT more likely slips at the nip N2 and
falls in the apparatus depth direction (the vibration direction of
the conductive belt CB) as the formation width of the toner image
G1 with the toner MT is larger and the area coverage of the toner
MT is higher. The inventor of this application found that, if the
toner image G1 with the toner MT is in an area A2 in FIG. 10, an
image in which arrangement unevenness of the flat metal pigment MP
is more likely visually recognized is formed. Owing to this, in
this exemplary embodiment, if the predetermined condition is
satisfied (the region A1 in FIG. 9), it is assumed that the region
A2 in FIG. 10 is included.
[0078] In contrast, in the case of the image forming apparatus 10
(the transfer device 30) of this exemplary embodiment, if the
controller 60 determines YES in determining step S200 and in
determining step S210, the toner image G1 on the transfer belt TB
is second transferred on a medium P at the nip N2 while the first
removing portion 92 or the second removing portion 94 is not driven
as shown in FIG. 8.
[0079] Accordingly, with the image forming apparatus 10 (the
transfer device 30) of this exemplary embodiment, an image with a
smaller periodical variation in posture of the flat metal pigment
MP may be formed as compared with the image forming apparatus (the
transfer device) in which the toner image G1 with the toner MT is
second transferred on the medium P while the first removing portion
92 and the second removing portion 94 are driven (rotated).
Second Effect
[0080] For the second effect, the image forming apparatus 10 (the
transfer device 30) of this exemplary embodiment is described in
comparison with an image forming apparatus (a transfer device) of a
comparative exemplary embodiment described below. In the image
forming apparatus of the comparative exemplary embodiment, step
S210 in FIG. 8 is omitted (see FIG. 17). In other point of view,
the image forming apparatus of the comparative exemplary embodiment
does not determine whether or not a toner image G1 to be formed
with the toner MT satisfies the predetermined condition. The image
forming apparatus of the comparative exemplary embodiment has a
similar configuration to that of the image forming apparatus 10
(the transfer device 30) of this exemplary embodiment except the
above-described point. It is to be noted that the above-described
comparative exemplary embodiment pertains to the technical scope of
the invention.
[0081] In the image forming apparatus of the comparative exemplary
embodiment, if the toner image G1 with the toner MT is formed, even
though the controller 60 determines YES in determining step S210,
an image forming operation is executed in the special mode (see
FIG. 17). Owing to this, if the image forming apparatus of the
comparative exemplary embodiment forms a toner image G1 with the
toner MT satisfying the predetermined condition, an image in which
arrangement unevenness of the flat metal pigment MP is more hardly
visually recognized may be formed as compared with the image
forming apparatus in which the removing unit 90 that removes a
toner T adhering to the conductive belt CB is driven. However, if
an image is formed with the toner MT and if the predetermined
condition is not satisfied (that is, if a toner image is in a
region other than the region A1 in FIG. 9), the image forming
apparatus of the comparative exemplary embodiment is not able to
execute the removing operation for the toner T adhering to the
conductive belt CB by using the removing unit 90.
[0082] In contrast, if the controller 60 determines NO in
determining step S210, the image forming apparatus 10 (the transfer
device 30) of this exemplary embodiment executes an image forming
operation in the normal mode as shown in FIG. 8.
[0083] Accordingly, in the image forming apparatus 10 (the transfer
device 30) of this exemplary embodiment, if the controller 60
causes a toner image G1 with the toner MT which does not satisfy
the predetermined condition to be formed, the removing operation
for the toner T adhering to the conductive belt CB is able to be
executed.
Third Effect
[0084] For the third effect, the image forming apparatus 10 (the
transfer device 30) of this exemplary embodiment is described in
comparison with an image forming apparatus (a transfer device) of a
comparative exemplary embodiment described below. In the image
forming apparatus of the comparative exemplary embodiment, the
controller 60 does not cause the power supply PS to apply a voltage
to the first removing portion 92 or the second removing portion 94
in step S230 in FIG. 8. The image forming apparatus (the transfer
device) of the comparative exemplary embodiment has a similar
configuration to that of the image forming apparatus 10 (the
transfer device 30) of this exemplary embodiment except the
above-described point.
[0085] In the image forming apparatus of the comparative exemplary
embodiment, part of the toner T adhering to the conductive belt CB
circulates together with the conductive belt CB, and contacts the
conductive brushes 92A and 94A that are stopped and in contact with
the conductive belt CB. However, since a voltage is not applied to
the conductive brush 92A or 94A, the toner T on the conductive belt
CB being in contact with the conductive brushes 92A and 94A is
hardly transferred from the conductive belt CB to the conductive
brushes 92A and 94A. Hence the toner T may circulate together with
the conductive belt CB and reach the nip N2. When the toner T
reaches the nip N2, the toner T adheres to the back surface of the
medium P (a surface of the medium P opposite to a surface on which
the toner image G1 is transferred), and may contaminate the back
surface of the medium P.
[0086] In contrast, in the image forming apparatus 10 (the transfer
device 30) of this exemplary embodiment, as shown in FIG. 8, if the
controller 60 determines YES in determining step S210, the
controller 60 causes the power supply PS to apply a voltage to the
first removing portion 92 and the second removing portion 94 in
step S230. Owing to this, the toner T on the conductive belt CB
being in contact with the conductive brushes 92A and 94A is likely
transferred from the conductive belt CB to the conductive brushes
92A and 94A.
[0087] Accordingly, in the image forming apparatus 10 (the transfer
device 30) of this exemplary embodiment, if the controller 60
causes a toner image G1 with the toner MT which satisfies the
predetermined condition to be formed, the amount of toner T to be
transferred from the conductive belt CB to the conductive brushes
92A and 94A is larger than that of the image forming apparatus that
does not apply a voltage to the conductive brush 92A or 94A.
Fourth Effect
[0088] For the fourth effect, the image forming apparatus 10 (the
transfer device 30) of this exemplary embodiment is described in
comparison with an image forming apparatus (a transfer device) of a
comparative exemplary embodiment described below. In the image
forming apparatus of the comparative exemplary embodiment, step
S240 in the special mode in FIG. 8 is omitted. That is, in the case
of the image forming apparatus of the comparative exemplary
embodiment, the maintenance operation of the second transfer unit
36 is not executed after step S230 in the special mode. The image
forming apparatus (the transfer device) of the comparative
exemplary embodiment has a similar configuration to that of the
image forming apparatus 10 (the transfer device 30) of this
exemplary embodiment except the above-described point.
[0089] In the case of the image forming apparatus of the
comparative exemplary embodiment, the toner T on the conductive
belt CB being in contact with the conductive brushes 92A and 94A is
transferred from the conductive belt CB to the conductive brushes
92A and 94A during the transfer operation to the medium P. In the
case of the image forming apparatus of the comparative exemplary
embodiment, after the controller 60 causes the second transfer unit
36 to complete transferring the toner image G1 formed by the
single-color unit 21G onto the medium P (after the transfer
operation in accordance with job data is completed), the image
forming operation is ended while the toner T is transferred to the
conductive brushes 92A and 94A. Owing to this, in the case of the
image forming apparatus of the comparative exemplary embodiment, if
a transfer operation is executed in accordance with the next job
data, the toner T transferred to the conductive brushes 92A and 94A
circulates together with the conductive belt CB and reaches the nip
N2. When the toner T reaches the nip N2, the toner T adheres to the
back surface of the medium P (a surface of the medium P opposite to
a surface on which the toner image G1 is transferred).
[0090] In contrast, in the image forming apparatus 10 (the transfer
device 30) of this exemplary embodiment, as shown in FIG. 8, after
step S230, the maintenance operation of the second transfer unit 36
is executed in step S240. Owing to this, in the case of the image
forming apparatus 10 (the transfer device 30) of this exemplary
embodiment, the toner T transferred to the conductive brushes 92A
and 94A by the metal shafts 92B and 94B is removed from the
conductive brushes 92A and 94A, and then the image forming
operation is ended.
[0091] Accordingly, in the image forming apparatus 10 (the transfer
device 30) of this exemplary embodiment, the toner T transferred to
the conductive brushes 92A and 94A is removed from the conductive
brushes 92A and 94A after the transfer operation in accordance with
the job data is ended and before the image forming operation is
ended.
Second Exemplary Embodiment
[0092] Next, a second exemplary embodiment is described. In the
following description, if the same component as that used in the
first exemplary embodiment is used in this exemplary embodiment,
the reference sign of the component is used without change.
Configuration
[0093] As shown in FIG. 12, an image forming apparatus 10A (a
transfer device 30A) of this exemplary embodiment differs from the
image forming apparatus 10 of the first exemplary embodiment (see
FIG. 8) in that the non-transfer image G2 is not formed in step
S220 in the special mode. The image forming apparatus 10A of this
exemplary embodiment has a configuration similar to that of the
image forming apparatus 10 of the first exemplary embodiment except
the above-described point.
Effect
[0094] In the case of the image forming apparatus 10A of this
exemplary embodiment, if the controller 60 causes the image forming
operation to be executed in the special mode, the controller 60
does not cause the single-color unit 21 to form the non-transfer
image G2. Owing to this, the amount of toner T adhering to the
conductive belt CB is decreased. Other effect of this exemplary
embodiment is similar to the effects (first to fourth effects) of
the first exemplary embodiment.
Third Exemplary Embodiment
[0095] Next, a third exemplary embodiment is described. In the
following description, if the same component as that used in the
first exemplary embodiment is used in this exemplary embodiment,
the reference sign of the component is used without change.
Configuration
[0096] As shown in FIG. 13, an image forming apparatus 10B of this
exemplary embodiment includes a rotational brush 100 and a blade
102 at a removing unit 90B configuring a second transfer unit 36B,
instead of the first removing portion 92 and the second removing
portion 94 configuring the removing unit 90, as compared with the
image forming apparatus 10 (see FIG. 3) of the first exemplary
embodiment. The rotational brush 100 is an example of a rotational
body. The rotational brush 100 rotates around its axis in a state
biting into the conductive belt CB, and contacts the conductive
belt CB. Also, the blade 102 contacts the conductive belt CB at a
position located downstream of the rotational brush 100 and
upstream of the nip N2 in the circulation direction of the
conductive belt CB, and removes the toner T adhering to the
conductive belt CB. Also, in the case of the image forming
apparatus 10B of this exemplary embodiment, the controller 60
causes the image forming operation to be executed according to a
flowchart in FIG. 14. The flowchart in FIG. 14 differs from the
flowchart of the first exemplary embodiment (see FIG. 8) in step
S230, step S240, and step S260. To be specific, the controller 60
does not cause the rotational brush 100 to rotate (or even a
voltage is not applied) in step S230 of this exemplary embodiment.
Also, when the controller 60 causes the rotational brush 100 to
rotate in step S240, the controller 60 does not cause a voltage to
be applied. The image forming apparatus 10B of this exemplary
embodiment has a configuration similar to that of the image forming
apparatus 10 of the first exemplary embodiment except the
above-described point.
Effect
[0097] Effects of this exemplary embodiment are similar to the
effects of the first exemplary embodiment (first, second, and
fourth effects).
Fourth Exemplary Embodiment
[0098] Next, a fourth exemplary embodiment is described. In the
following description, if the same component as that used in the
first and third exemplary embodiments is used in this exemplary
embodiment, the reference sign of the component is used without
change.
Configuration
[0099] As shown in FIG. 15, an image forming apparatus 10C of this
exemplary embodiment includes a blade 102 and an auger 104 at a
removing unit 90C configuring a second transfer unit 36C, instead
of the first removing portion 92 and the second removing portion 94
configuring the removing unit 90, as compared with the image
forming apparatus 10 (see FIG. 3) of the first exemplary
embodiment. The auger 104 is an example of a rotational body. The
auger 104 is separated from the conductive belt CB and is arranged
below the conductive belt CB. The auger 104 rotates around its
axis, transports the toner T accumulated in the housing 96 in the
axial direction (the apparatus depth information), and is output
from an opening (not illustrated) formed in a wall surface of the
housing 96. The output toner T is housed in a waste toner tank (not
illustrated). Also, in the case of the image forming apparatus 10C
of this exemplary embodiment, the controller 60 causes the image
forming operation to be executed according to a flowchart in FIG.
16. The flowchart in FIG. 16 differs from the flowchart of the
first exemplary embodiment (see FIG. 8) in step S230, step S240,
and step S260. To be specific, the controller 60 does not cause the
auger 104 to rotate (or even a voltage is not applied) in step S230
of this exemplary embodiment. Also, when the controller 60 causes
the auger 104 to rotate in step S240, the controller 60 does not
cause a voltage to be applied. The image forming apparatus 10C of
this exemplary embodiment has a configuration similar to that of
the image forming apparatus 10 of the first exemplary embodiment
except the above-described point.
Effect
[0100] Other effect of this exemplary embodiment is similar to the
effects of the first exemplary embodiment (first, second, and
fourth effects).
[0101] The invention has been described above in detail based on
the specific exemplary embodiments; however, the invention is not
limited to the above-described exemplary embodiments and other
exemplary embodiment may be employed within the scope of the
technical idea of the invention.
[0102] For example, in the image forming apparatus 10 of the first
exemplary embodiment, the controller 60 determines determining step
S200, determining step S210, etc., and executes the image forming
operation (mode) in accordance with the determination. However, the
mode executed in accordance with each determination is merely an
example, and the image forming apparatus 10 of the first exemplary
embodiment may include other mode. The image forming apparatuses
10A, 10B, and 10C of other exemplary embodiments may be configured
similarly.
[0103] Also, the toner MT used by the image forming apparatus 10 of
the first exemplary embodiment is gold color. However, the toner MT
may not be gold color as long as the toner MT is a flat toner
containing a flat metal pigment. For example, the toner MT may be
silver color. The image forming apparatuses 10A, 10B, and 10C of
other exemplary embodiments may be configured similarly.
[0104] Also, as shown in FIG. 1, in the image forming apparatus 10
of the first exemplary embodiment, the single-color unit 21G that
uses the toner MT is arranged at the most upstream side in the
moving direction of the transfer belt TB in the toner image forming
unit 20. However, the arrangement order of the single-color unit
21G may be any order as long as the toner image forming unit 20
includes the single-color unit 21G.
[0105] Also, in the image forming apparatus 10 of the first
exemplary embodiment, the second transfer voltage is applied to the
BUR 80 and the conductive roller 72 configuring the second transfer
portion 70 is grounded. However, the second transfer voltage may be
applied to the conductive roller 72 and the BUR 80 may be
grounded.
[0106] Also, in the image forming apparatus 10 of the first
exemplary embodiment, the conductive belt CB is an example of the
transfer unit. However, instead of providing the conductive belt CB
and the tension roller 74 like the second transfer portion 70, for
example, the nip N2 may be formed by the conductive roller 72 and
the transfer belt TB. In this case, the conductive roller 72 serves
as an example of the transfer unit. The image forming apparatuses
10A, 10B, and 10C of other exemplary embodiments may be configured
similarly.
[0107] Also, in the image forming apparatus 10 of the first
exemplary embodiment, the removing unit 90 configuring the second
transfer unit 36 includes the first removing portion 92 and the
second removing portion 94. However, one of the first removing
portion 92 and the second removing portion 94 may be omitted as
long as the removing unit 90 includes a rotational body that
rotates around its axis. The image forming apparatuses 10A of the
second exemplary embodiment may be configured similarly.
[0108] Also, in the image forming apparatus 10 of the first
exemplary embodiment, voltages are applied to the metal shafts 92B
and 94B of the first removing portion 92 and the second removing
portion 94. However, voltages may be directly applied to the
conductive brushes 92A and 94A. In this case, instead of the metal
shafts 92B and 94B, the first removing portion 92 and the second
removing portion 94 may have plates that contact the conductive
brushes 92A and 94A, and the plates may remove the toner T held by
the conductive brushes 92A and 94A from the conductive brushes 92A
and 94A. In this case, the plates are each an example of a removing
portion.
[0109] In the image forming apparatus 10 of the first exemplary
embodiment, the above-described predetermined condition is that the
ratio of the formation width of the toner MT with respect to the
width of the medium P is 2/3 or larger (1 or smaller), and the area
coverage of the toner MT is 95% or higher (100% or lower) as shown
in the graph in FIG. 9. However, the condition may be other
condition because the condition is based on the sensory evaluation
for evaluating whether or not an image whose arrangement unevenness
of the flat metal pigment MP is likely visually recognized is
formed. For example, the predetermined condition may be that the
ratio of the formation width of the toner MT with respect to the
width of the medium P is 1/2 or larger (1 or smaller) and the area
coverage of the toner MT is 95% or higher (100% or lower).
[0110] In the description of the exemplary embodiments, first to
fourth exemplary embodiments are provided. However, of course, an
exemplary embodiment with the configurations of the respective
exemplary embodiments combined may be included in the technical
scope of the invention.
[0111] The foregoing description of the exemplary embodiments of
the present invention has been provided for the purposes of
illustration and description. It is not intended to be exhaustive
or to limit the invention to the precise forms disclosed.
Obviously, many modifications and variations will be apparent to
practitioners skilled in the art. The embodiments were chosen and
described in order to best explain the principles of the invention
and its practical applications, thereby enabling others skilled in
the art to understand the invention for various embodiments and
with the various modifications as are suited to the particular use
contemplated. It is intended that the scope of the invention be
defined by the following claims and their equivalents.
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